The present invention relates generally to hermetic compressor assemblies, particularly those having drive shafts which are substantially vertically oriented and, more particularly, to lubricating systems for such compressor assemblies.
Previous systems for supplying oil from a compressor sump located near the bottom of a compressor assembly to the lubricated bearings, which may be located near the top of the compressor assembly, have provided for conveying oil in a conduit which extends longitudinally through a rotating compressor drive shaft, perhaps nearly the full height of the compressor assembly on compressor start up. Ordinarily, the oil is driven upwards through this conduit by means of a centrifugal or positive displacement pump. Priming this conduit with oil from the sump takes time, and must be done each time the compressor starts up. This priming time may expose the bearings, particularly those bearings located near the top of the compressor, to periods during which no oil is being provided thereto. Consequently, the bearings may at least temporarily operate with a marginal or inadequate lubricating oil supply, stressing the bearings and leading to their premature wear and possible failure of the compressor. Notably, the bearings may be radial or thrust bearings, whether hydrodynamic or of any other kind (e.g., roller or ball type), and may be formed by any of a number of various interfacing surfaces; herein xe2x80x9cbearingxe2x80x9d should be generally interpreted as including any points provided with oil by a lubrication system.
Further, the oil being provided from the sump to the bearings often contains an amount of refrigerant. As the oil in the lubrication system experiences changes in pressure and/or temperature, the refrigerant is vaporized and flashed from the oil. The flashed refrigerant may form gas pockets through or past which oil flow is inhibited. The flashed refrigerant vapor may also be carried along with the oil flowing through the lubrication system, taking up space in the flow which the oil would otherwise occupy. It can thus be understood that refrigerant vapor in the lubrication system can inhibit the proper operation of the system, and result in an inadequate supply of oil being provided to the bearings.
Further, previous compressor lubrication systems often allow any debris (e.g., metal particles) present in the oil to be circulated with the oil to the bearings, which may deposit on and/or prematurely wear the bearing.
It is therefore desirable to provide a compressor lubrication system which shortens priming time on compressor startup, facilitates the removal of flashed refrigerant vapor from the oil, and prevents debris from reaching the bearings with the oil.
The present invention addresses the above-mentioned shortcomings of previous compressors having compressor lubrication systems which direct the oil flow substantially vertically from the sump to the bearings, and provides the above-mentioned desirable advantages over those compressors.
The present invention provides a compressor assembly including a housing, a compression mechanism disposed in the housing, a sump located in the housing, the sump containing liquid lubricant, a conduit extending between the compression mechanism and the sump, the compression mechanism and the sump being in fluid communication through the conduit, lubricant in the sump being provided to the compression mechanism through the conduit, and a reservoir containing liquid lubricant located between the compression mechanism and the sump. The reservoir is in fluid communication with the conduit, and the compression mechanism and the reservoir are in fluid communication through the conduit. Lubricant in the reservoir is provided to the compression mechanism through the conduit.
The present invention also provides a compressor assembly including a housing, a compression mechanism disposed in the housing, a sump located in the housing, the sump containing liquid lubricant, and a conduit extending between the compression mechanism and the sump. The compression mechanism and the sump are in fluid communication through the conduit, and lubricant in the sump is provided to the compression mechanism through the conduit. Also included are means in fluid communication with the conduit for storing liquid lubricant between the compression mechanism and the sump, and providing the stored lubricant to the compression mechanism through the conduit upon startup of the compressor assembly.
The present invention also provides a compressor assembly including a housing, a compression mechanism disposed in the housing, and a motor disposed in the housing and having a stator and a rotor, the rotor operably coupled to the compression mechanism. A sump is located in the housing, the sump containing liquid lubricant. A conduit is rotatably fixed to the rotor and extends between the compression mechanism and the sump, the compression mechanism and the sump are in fluid communication through the conduit, and lubricant in the sump is provided to the compression mechanism through the conduit. Also provided is a reservoir containing liquid lubricant located between the compression mechanism and the sump, and surrounding the conduit. The reservoir is in fluid communication with the conduit, and the compression mechanism and the reservoir are in fluid communication through the conduit. Lubricant in the reservoir is provided to the compression mechanism through the conduit.